Market anomaly

A market anomaly (or market inefficiency) in a financial market is a price and/or rate of return distortion that seems to contradict the efficient-market hypothesis. A market anomaly (or market inefficiency) in a financial market is a price and/or rate of return distortion that seems to contradict the efficient-market hypothesis. Some of the main causes, why market anomalies happen, are structural factors such as unfair competition, lack of market transparency, regulatory actions, etc. Another explanation is presented by behavioral economics in the form of behavioral biases (cognitive bias, emotional bias, reflexive bias), conservatism (people are averse to new information and rely heavily on old beliefs) or overconfidence (investors overestimate their own abilities and make irrational choices). Market anomalies can be calendar related (they appear periodically on given calendar events), fundamental and technical (they appear when trading using technical analysis).